Process for the preparation of hydroxy-vinyl-aromatic polymers or copolymers by anionic or controlled radical polymerization

ABSTRACT

The instant invention relates to a process for the preparation of hydroxy-vinyl-aromatic polymers in particular 4-hydroxystyrene polymers or copolymers by anionic or controlled radical polymerization of the respective monomer, wherein the hydroxy functionality is blocked with a protective group which is subsequently removed by reacting it with a halosilane reagent. The resulting (co)polymers have a narrow polydispersity and are useful for manufacturing photoresists.

The instant invention relates to a process for the preparation ofhydroxy-vinyl-aromatic polymers in particular 4-hydroxystyrene polymersor copolymers by anionic polymerization or controlled radicalpolymerization of the respective monomer, wherein the hydroxyfunctionality is blocked with a protective group, which is subsequentlyremoved by reacting it with a halosilane reagent. The resulting(co)polymers have a narrow polydispersity and are useful formanufacturing photoresists.

Hydroxy-vinyl aromatic polymers are very useful binder components fornegative and positive acting photoresists. Important properties of thephotoresist formulation, such as resolution and time for developing,depend strongly on the molecular weight of the hydroxy-vinyl aromaticpolymers and of its molecular distribution.

A narrow molecular weight distribution is of high importance since itinfluences the glass transition temperature of the polymer. When thepolymer is used in a resist formulation a glass transition temperatureof above 130° C. is desirable.

Many attempts have therefore been made to preparepoly-(4-hydroxy-styrene) with a well defined molecular weight and narrowmolecular weight distribution. One approach has been, to use anionicpolymerization for the preparation of poly-(4-hydroxy-styrene). Thispolymerization process is not easy to handle, since traces ofimpurities, such as oxygen or water, have a negative impact on thepolymer's properties.

Recently a method for the preparation of poly-(4-hydroxy-styrene) bycontrolled radical polymerization has been disclosed in U.S. Pat. No.6,107,425. The method described therein uses nitroxyl radicals oralkoxyamines as regulating/initiating compounds. In particular2,2,6,6-tetramethyl-piperidine-1-oxyl is used as regulating agent.

Controlled polymerization using alkoxyamines or stable free nitroxylradicals together with a source of free radicals (radical initiator) isknown. U.S. Pat. No. 4,581,429 to Solomon et al., issued Apr. 8, 1986,discloses a free radical polymerization process which controls thegrowth of polymer chains to produce short chain or oligomerichomopolymers and copolymers, including block and graft copolymers. Thistype of polymerization is frequently called “living polymerization”. Theprocess employs an initiator having the formula (in part) R′R″N—O—X,where X is a free radical species capable of polymerizing unsaturatedmonomers. The reactions typically have low conversion rates.Specifically mentioned radical R′R″N—O. groups are derived from 1,1,3,3tetraethylisoindoline, 1,1,3,3 tetrapropylisoindoline, 2,2,6,6tetramethylpiperidine, 2,2,5,5 tetramethylpyrrolidine ordi-t-butylamine.

U.S. Pat. No. 5,322,912 to Georges et al. issued Jun. 21, 1994 disclosesa polymerization process using a free radical initiator, a polymerizablemonomer compound and a stable free radical agent of the basic structureR′R″N—O. for the synthesis of homopolymers and block copolymers.

Since 4-hydroxy-styrene itself is thermally not very stable it canundergo spontaneous polymerization, or the free OH-group can interactwith the regulating or initiating radicals in the controlled radicalpolymerization process. U.S. Pat. No. 6,107,425 suggests therefore tofirstly react the OH-group with a protective group, then to polymerizeunder controlled conditions and finally to remove the protective groupby an acidic or basic treatment to obtain again the free OH-group.

All protective groups suggested in U.S. Pat. No. 6,107,425 are groups,which can be removed by acid or base treatment. Examples are acetyl,trialkylsilyl or sulfonyl groups.

The present invention differs from this prior art process in that aprotective group is used, which can be removed by reaction with ahalosilane reagent, such as for example iodotrimethylsilane, which canbe prepared in situ, for example, from commercially easily availablechlorotrimethylsilane and sodium iodide as described in J. Org. Chem.,44(8), 1247, 1979.

It has been surprisingly found that the reaction with a halosilaneresults in very pure hydroxy-vinyl aromatic polymers or copolymers, dueto the mild reaction conditions applied. The resulting polymer is freeof any discoloration and in particular shows high optical transmittancearound 248 nm, which is important when the polymer is used in a resistformulation.

Furthermore nitroxyl end groups coming from the controlled radicalpolymerization are also removed under these conditions and the remainingpolymer is therefore thermally stable. This is also an important aspectfor its use in resist formulations as for example described inJP2000-26535, Sumitomo Chemical Co., Ltd.

One aspect of the instant invention is a process for the preparation ofa narrow molecular weight distributed hydroxy-vinyl aromatic oligomer,cooligomer, polymer or copolymer with a polydispersity M_(w)/M_(n)between 1 and 2, which process comprises the steps reacting acomposition of at least one monomer of formula I

wherein

R₁ is H or CH₃;

R₂ and R₃ are independently hydrogen, C₁-C₈alkyl, C₁-C₈alkoxy,C₁-C₈alkoxycarbonyl, C₁-C₈alkylthio, C₁-C₈dialkylamino,trihalogenmethyl;

R₄ is C₁-C₁₂alkyl or benzyl which is unsubstituted or substituted withone or two C₁-C₈alkyl, C₁-C₈alkoxy, C₁-C₈alkoxycarbonyl, C₁-C₈alkylthio,C₁-C₈dialkylamino, trihalogenmethyl, halogen; or R₄ is a groupphenyl(methyl)CH—, (phenyl)₂CH—, C₁-C₁₂alkyl-O—C(O)—, phenyl-CH₂—O—C(O)—or (phenyl)₂CH—O—C(O)—;

a1) in the presence of at least one nitroxylether having the structuralelement

wherein X represents a group having at least one carbon atom and is suchthat the free radical X. derived from X is capable of initiatingpolymerization of ethylenically unsaturated monomers; or

a2) in the presence of at least one stable free nitroxyl radical

and a free radical initiator; or

a3) in the presence of a compound of formula (III)

(III) and a catalytically effective amount

of an oxidizable transition metal complex catalyst, wherein

p represents a number greater than zero and defines the number ofinitiator fragments;

q represents a number greater than zero;

[ln] represents a radically transferable atom or group capable ofinitiating polymerization and -[Hal] represents a leaving group; or

a4) in an anionic polymerization reaction in the presence of a metal ororgano metal catalyst; and optionally simultaneously or in a subsequentstep with one or more ethylenically unsaturated monomers different fromthose of formula (I); and

b) isolating the resulting polymer and subjecting it to a reaction witha halosilane giving a polymer with repeating units of formula II

and with a degree of OH-groups of between 10 mol % and 100 mol %, basedon the molar amount of protected hydroxy-vinyl aromatic monomer offormula I.

Halosilane is chloro-, bromo- or iodosilane. In a specific embodiment ofthe invention halosilane is iodosilane.

In a preferred embodiment of the invention polymerization is carried outaccording to steps a1) or a2).

The radical polymerization reaction of steps a1), a2) and a3) ispreferably carried out at a temperature between 50° C. and 180° C.;

The anionic polymerization reaction may for example be carried out at atemperature between −100° C. and 150° C.

Preferred is a process wherein in formula I R₁ is H; R₂ and R₃ are H;OR₄ is in the 4-position and R₄ is C₁-C₄alkyl, benzyl,C₁-C₄alkoxycarbonyl or benzyloxycarbonyl.

Most preferably R₄ is tert.-butyl or benzyl.

The starting monomer, 4-tert-butoxystyrene, is commercially availablefrom Hokko Chemical Inustry Co., Ltd. Another starting monomer,4-benzyloxystyrene, can be prepared for example from 4-acetoxystyreneaccording to EP 589 621 or from 4-benzyloxyacetophenone according toTetrahedron 235, (1975). Other substituted styrene derivatives offormula (I) can be prepared in analogy.

The nitroxylethers and nitroxyl radicals are principally known from U.S.Pat. No. 4,581,429 or EP-A-621 878. Particularly useful are the openchain compounds described in WO 98/13392, WO 99/03894 and WO 00/07981,the piperidine derivatives described in WO 99/67298 and GB 2335190 orthe heterocyclic compounds described in GB 2342649 and WO 96/24620.Further suitable nitroxylethers and nitroxyl radicals are described inWO 02/4805 and in WO 02/100831.

Preferably the nitroxylether of step a1) is of formula A, B or O,

wherein

m is 1,

R is hydrogen, C₁-C₁₈alkyl which is uninterrupted or interrupted by oneor more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalentradical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, ofa cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or anα,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of anaromatic carboxylic acid having 7 to 15 carbon atoms;

p is 1;

R₁₀₁ is C₁-C₁₂alkyl, C₅-C₇cycloalkyl, C₇-C₈aralkyl, C₂-C₁₈alkanoyl,C₃-C₅alkenoyl or benzoyl;

R₁₀₂ is C₁-C₁₈alkyl, C₅-C₇cycloalkyl, C₂-C₈alkenyl unsubstituted orsubstituted by a cyano, carbonyl or carbamide group, or is glycidyl, agroup of the formula —CH₂CH(OH)-Z or of the formula —CO-Z or —CONH-Zwherein Z is hydrogen, methyl or phenyl;

G₆ is hydrogen and G₅ is hydrogen or C₁-C₄alkyl,

G₁ and G₃ are methyl and G₂ and G₄ are ethyl or propyl or G₁ and G₂ aremethyl and G₃ and G₄ are ethyl or propyl; and

X is selected from the group consisting of —CH₂-phenyl, CH₃CH-phenyl,(CH₃)₂C-phenyl, (C₅-C₆cycloalkyl)₂CCN, (CH₃)₂CCN,

—CH₂CH═CH₂, CH₃CH—CH═CH₂ (C₁-C₄alkyl)CR₂₀—C(O)-phenyl,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkoxy,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—N-di(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—NH(C₁-C₄)alkyl, (C₁-C₄)alkyl-CR₂₀—C(O)—NH₂,wherein

R₂₀ is hydrogen or (C₁-C₄)alkyl.

More preferably in formula A, B and O

R is hydrogen, C₁-C₁₈alkyl, cyanoethyl, benzoyl, glycidyl, a monovalentradical of an aliphatic, carboxylic acid;

R₁₀₁ is C₁-C₁₂alkyl, C₇-C₈aralkyl, C₂-C₁₈alkanoyl, C₃-C₅alkenoyl orbenzoyl;

R₁₀₂ is C₁-C₁₈alkyl, glycidyl, a group of the formula —CH₂CH(OH)-Z or ofthe formula —CO-Z, wherein Z is hydrogen, methyl or phenyl; and

X is CH₃—CH-phenyl.

The above compounds and their preparation are described in GB 2335190and GB 2 361 235.

Another preferred group of nitroxylethers of step a1) are those offormula (Ic), (Id), (Ie), (If), (Ig) or (Ih)

wherein R₂₀₁, R₂₀₂, R₂₀₃ and R₂₀₄ independently of each other areC₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl, C₁-C₁₈alkyl, C₃-C₁₈alkenyl,C₃-C₁₈alkinyl which are substituted by OH, halogen or a group—O—C(O)—R₂₀₅, C₂-C₁₈alkyl which is interrupted by at least one O atomand/or NR₂₀₅ group, C₃-C₁₂cycloalkyl or C₆-C₁₀aryl or R₂₀₁ and R₂₀₂and/or R₂₀₃ and R₂₀₄ together with the linking carbon atom form aC₃-C₁₂cycloalkyl radical;

R₂₀₅, R₂₀₆ and R₂₀₇ independently are hydrogen, C₁-C₁₈alkyl orC₆-C₁₀aryl;

R₂₀₈ is hydrogen, OH, C₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl,C₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl which are substituted by oneor more OH, halogen or a group —O—C(O)—R₂₀₅, C₂-C₁₈alkyl which isinterrupted by at least one O atom and/or NR₂₀₅ group, C₃-C₁₂cycloalkylor C₆-C₁₀aryl, C₇-C₉phenylalkyl, C₅-C₁₀heteroaryl, —C(O)—C₁-C₁₈alkyl,—O—C₁-C₁₈alkyl or —COOC₁-C₁₈alkyl;

R₂₀₉, R₂₁₀, R₂₁₁ and R₂₁₂ are independently hydrogen, phenyl orC₁-C₁₈alkyl; and

X is selected from the group consisting of —CH₂-phenyl, CH₃CH-phenyl,(CH₃)₂C-phenyl, (C₅-C₆cycloalkyl)₂CCN, (CH₃)₂CCN,

—CH₂CH═CH₂, CH₃CH—CH═CH₂ (C₁-C₄alkyl)CR₂₀—C(O)-phenyl,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkoxy,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—N-di(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—NH(C₁-C₄)alkyl, (C₁-C₄)alkyl-CR₂₀—C(O)—NH₂,wherein

R₂₀ is hydrogen or (C₁-C₄)alkyl.

More preferably in formula (Ic), (Id), (Ie), (f), (Ig) and (Ih) at leasttwo of R₂₀₁, R₂₀₂, R₂₀₃ and R₂₀₄ are ethyl, propyl or butyl and theremaining are methyl; or

R₂₀₁ and R₂₀₂ or R₂₀₃ and R₂₀₄ together with the linking carbon atomform a C₅-C₆cycloalkyl radical and one of the remaining substituents isethyl, propyl or butyl.

Most preferably X is CH₃CH-phenyl.

The above compounds and their preparation is described in GB 2342649.

When a nitroxyl radical is used together with a free radical initiator,the nitroxyl radical of step a2) is preferably of formula A′, B′ or O′,

wherein

m is 1,

R is hydrogen, C₁-C₁₈alkyl which is uninterrupted or interrupted by oneor more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalentradical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, ofa cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or anα,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of anaromatic carboxylic acid having 7 to 15 carbon atoms;

p is 1;

R₁₀₁ is C₁-C₁₂alkyl, C₅-C₇cycloalkyl, C₇-C₈aralkyl, C₂-C₁₈alkanoyl,C₃-C₅alkenoyl or benzoyl;

R₁₀₂ is C₁-C₁₈alkyl, C₅-C₇cycloalkyl, C₂-C₈alkenyl unsubstituted orsubstituted by a cyano, carbonyl or carbamide group, or is glycidyl, agroup of the formula —CH₂CH(OH)-Z or of the formula —CO-Z or —CONH-Zwherein Z is hydrogen, methyl or phenyl;

G₆ is hydrogen and G₅ is hydrogen or C₁-C₄alkyl, and

G₁ and G₃ are methyl and G₂ and G₄ are ethyl or propyl or G₁ and G₂ aremethyl and G₃ and G₄ are ethyl or propyl.

More preferably in formula A′, B′ and O′

R is hydrogen, C₁-C₁₈alkyl, cyanoethyl, benzoyl, glycidyl, a monovalentradical of an aliphatic, carboxylic acid;

R₁₀₁ is C₁-C₁₂alkyl, C₇-C₈aralkyl, C₂-C₁₈alkanoyl, C₃-C₅alkenoyl orbenzoyl;

R₁₀₂ is C₁-C₁₈alkyl, glycidyl, a group of the formula —CH₂CH(OH)-Z or ofthe formula —CO-Z, wherein Z is hydrogen, methyl or phenyl.

The above compounds and their preparation are described in GB 2335190and GB 2 361 235.

Another preferred group of nitroxyl radicals are those of formula (Ic′),(Id′), (Ie′), (If′), (Ig′) or (Ih′)

wherein R₂₀₁, R₂₀₂, R₂₀₃ and R₂₀₄ independently of each other areC₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl, C₁-C₁₈alkyl, C₃-C₁₈alkenyl,C₃-C₁₈alkinyl which are substituted by OH, halogen or a group—O—C(O)—R₂₀₅, C₂-C₁₈alkyl which is interrupted by at least one O atomand/or NR₂₀₅ group, C₃-C₁₂cycloalkyl or C₆-C₁₀aryl or R₂₀₁ and R₂₀₂and/or R₂₀₃ and R₂₀₄ together with the linking carbon atom form aC₃-C₁₂cycloalkyl radical;

R₂₀₅, R₂₀₆ and R₂₀₇ independently are hydrogen, C₁-C₁₈alkyl orC₆-C₁₀aryl;

R₂₀₈ is hydrogen, OH, C₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl,C₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl which are substituted by oneor more OH, halogen or a group —O—C(O)—R₂₀₅, C₂-C₁₈alkyl which isinterrupted by at least one O atom and/or NR₂₀₅ group, C₃-C₁₂cycloalkylor C₆-C₁₀aryl, C₇-C₉phenylalkyl, C₅-C₁₀heteroaryl, —C(O)—C₁-C₁₈alkyl,—O—C₁-C₁₈alkyl or —COOC₁-C₁₈alkyl; and

R₂₀₉, R₂₁₀, R₂₁₁, and R₂₁₂ are independently hydrogen, phenyl orC₁-C₁₈alkyl.

More preferably in formula (Ic′), (Id′), (Ie′), (If′), (Ig′) and (Ih′)at least two of R₂₀₁, R₂₀₂, R₂₀₃ and R₂₀₄ are ethyl, propyl or butyl andthe remaining are methyl; or

R₂₀₁ and R₂₀₂ or R₂₀₃ and R₂₀₄ together with the linking carbon atomform a C₆-C₆cycloalkyl radical and one of the remaining substituents isethyl, propyl or butyl.

The above compounds and their preparation is described in GB 2342649.

Other suitable compounds are the 4-imino piperidine derivatives offormula V

G₁₁, G₁₂, G₁₃ and G₁₄ are independently C₁-C₄alkyl or G₁₁ and G₁₂together and G₁₃ and G₁₄ together, or G₁₁ and G₁₂ together or G₁₃ andG₁₄ together are pentamethylene;

G₁₅ and G₁₆ are each independently of the other hydrogen or C₁-C₄alkyl;

k is 1, 2, 3, or 4

Y is O, NR₃₀₂ or when n is 1 and R₃₀₁ represents alkyl or aryl Y isadditionally a direct bond;

R₃₀₂ is H, C₁-C₁₈alkyl or phenyl;

if k is 1

R₃₀₁ is H, straight or branched C₁-C₁₈alkyl, C₃-C₁₈alkenyl orC₃-C₁₈alkinyl, which may be unsubstituted or substitued, by one or moreOH, C₁-C₈alkoxy, carboxy, C₁-C₈alkoxycarbonyl;

C₅-C₁₂cycloalkyl or C₆-C₁₂cycloalkenyl;

phenyl, C₇-C₉phenylalkyl or naphthyl which may be unsubstituted orsubstituted by one or more C₁-C₈alkyl, halogen, OH, C₁-C₈alkoxy,carboxy, C₁-C₈alkoxycarbonyl;

—C(O)—C₁-C₃₆alkyl, or an acyl moiety of α,β-unsaturated carboxylic acidhaving 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to15 carbon atoms;

—SO₃ ⁻Q⁺, —PO(O⁻Q⁺)₂, —P(O)(OR₂)₂, —SO₂—R₂, —CO—NH—R₂, —CONH₂, COOR₂, orSi(Me)₃,

wherein Q⁺ is H⁺, ammnonium or an alkali metal cation;

if k is2

R₃₀₁ is C₁-C₁₈alkylene, C₃-C₁₈alkenylene or C₃-C₁₈alkinylene, which maybe unsubstituted or substitued, by one or more OH, C₁-C₈alkoxy, carboxy,C₁-C₈alkoxycarbonyl; or xylylene; or

R₃₀₁ is a bisacyl radical of an aliphatic dicarboxylic acid having 2 to36 carbon atoms, or a cycloaliphatic or aromatic dicarboxylic acidhaving 8-14 carbon atoms;

if k is3,

R₃₀₁ is a trivalent radical of an aliphatic, cycloaliphatic or aromatictricarboxylic acid; and

if k is 4, R₃₀₁ is a tetravalent radical of an aliphatic, cycloaliphaticor aromatic tetracarboxylic acid.

Preferably G₁₆ is hydrogen and G₁₅ is hydrogen or C₁-C₄alkyl, inparticular methyl, and G₁₁ and G₁₃ are methyl and G₁₂ and G₁₄ are ethylor propyl or G₁₁ and G₁₂ are methyl and G₁₃ and G₁₄ are ethyl or propyl.

The 4 imino compounds of formula V can be prepared for example accordingto E. G. Rozantsev, A. V. Chudinov, V. D. Sholle.:Izv. Akad. Nauk. SSSR,Ser. Khim. (9), 2114 (1980), starting from the corresponding4-oxonitroxide in a condensation reaction with hydroxylamine andsubsequent reaction of the OH group.

Another possible reaction scheme is to first react the 4-oxonitroxidewith an amine or hydrazine to yield the corresponding imine as forexample described in FR 1503149.

It is, however also possible to firstly react the 4-oxopiperidine withhydroxylamine, hydrazine or with a semicarbacide to the correspondingimino-compound and oxidising the imino piperidine to the correspondingnitroxide.

The alkoxyamines of formula I may be prepared from the correspondingnitroxides as for example described in GB 2335190.

A particularly suitable process for the preparation of the compounds offormula (V) starts from the 4-oxo-alkoxyamines, the preparation of whichis also described in GB 2335190:

Since the 4-oxo-alkoxyamines already may have several asymmetricalcarbon atoms, a variety of stereo isomers is usually obtained as mixturewith different ratios of the individual isomers. It is however possibleto separate the individual isomers in pure form. Mixtures of the stereoisomers as well as the pure individual isomers are within the scope ofthe present invention.

The imino-compounds and their preparation are described in WO 02/100831.

The alkyl radicals in the various substituents may be linear orbranched. Examples of alkyl containing 1 to 18 carbon atoms are methyl,ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl,2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.

Alkenyl with 3 to 18 carbon atoms is a linear or branched radical as forexample propenyl, 2-butenyl, 3-butenyl, isobutenyl, n-2,4-pentadienyl,3-methyl-2-butenyl, n-2-octenyl, n-2-dodecenyl, iso-dodecenyl, oleyl,n-2-octadecenyl oder n4-octadecenyl.

Preferred is alkenyl with 3 bis 12, particularly preferred with 3 to 6carbon atoms.

Alkinyl with 3 to 18 is a linear or branched radical as for examplepropinyl

2-butinyl, 3-butinyl, n-2-octinyl, oder n-2-octadecinyl. Preferred isalkinyl with 3 to 12, particularly preferred with 3 to 6 carbon atoms.

Examples for hydroxy substituted alkyl are hydroxy propyl, hydroxy butylor hydroxy hexyl.

Examples for halogen substituted alkyl are dichloropropyl,monobromobutyl or trichlorohexyl.

C₂-C₁₈alkyl interrupted by at least one O atom is for example—CH₂—CH₂—O—CH₂—CH₃, —CH₂—CH₂—O—CH₃— or—CH₂—CH₂—O—CH₂—CH₂—CH₂—O—CH₂—CH₃—. It is preferably derived frompolyethlene glycol. A general description is —((CH₂)_(a)—O)_(b)—H/CH₃,wherein a is a number from 1 to 6 and b is a number from 2 to 10.

C₂-C₁₈alkyl interrupted by at least one NR₅ group may be generallydescribed as —((CH₂)_(a)—NR₅)_(b)—H/CH₃, wherein a, b and R₅ are asdefined above.

C₃-C₁₂cycloalkyl is typically, cyclopropyl, cyclopentyl,methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl ortrimethylcyclohexyl.

C₆-C₁₀aryl is for example phenyl or naphthyl, but also comprised areC₁-C₄alkyl substituted phenyl, C₁-C₄alkoxy substituted phenyl, hydroxy,halogen or nitro substituted phenyl. Examples for alkyl substitutedphenyl are ethylbenzene, toluene, xylene and its isomers, mesitylene orisopropylbenzene. Halogen substituted phenyl is for exampledichlorobenzene or bromotoluene.

Alkoxy substituents are typically methoxy, ethoxy, propoxy or butoxy andtheir corresponding isomers.

C₇-C₉phenylalkyl is benzyl, phenylethyl or phenylpropyl.

C₅-C₁₀heteroaryl is for example pyrrol, pyrazol, imidazol, 2,4,dimethylpyrrol, 1-methylpyrrol, thiophene, furane, furfural, indol,cumarone, oxazol, thiazol, isoxazol, isothiazol, triazol, pyridine,α-picoline, pyridazine, pyrazine or pyrimidine.

If R is a monovalent radical of a carboxylic acid, it is, for example,an acetyl, propionyl, butyryl, valeroyl, caproyl, stearoyl, lauroyl,acryloyl, methacryloyl, benzoyl, cinnamoyl orβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl radical.

C₁-C₁₈alkanoyl is for example, formyl, propionyl, butyryl, octanoyl,dodecanoyl but preferably acetyl and C₃-C₅alkenoyl is in particularacryloyl.

In general the polymerization processes using nitroxylethers a1) ornitroxyl radicals together with a free radical initiator a2) arepreferred. In particular polymerization process a1) is very suitable.

Particularly suitable nitroxylethers and nitroxyl radicals are those offormulae

The free radical initiator of component b2) is preferably a bis-azocompound, a peroxide, perester or a hydroperoxide.

Specific preferred radical sources are 2,2′-azobisisobutyronitrile,2,2′-azobis(2-methyl-butyronitrile),2,2′-azobis(2,4-dimethylvaleronitrile),2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile),1,1′-azobis(1-cyclohexanecarbonitrile), 2,2′-azobis(isobutyramide)dihydrate, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile,dimethyl-2,2′-azobisisobutyrate, 2-(carbamoylazo)isobutyronitrile,2,2′-azobis(2,4,4-trimethylpentane), 2,2′-azobis(2-methylpropane),2,2′-azobis(N,N′-dimethyleneisobutyramidine), free base orhydrochloride, 2,2′-azobis(2-amidinopropane), free base orhydrochloride,2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} or2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide;acetyl cyclohexane sulphonyl peroxide, diisopropyl peroxy dicarbonate,t-amyl perneodecanoate, t-butyl perneodecanoate, t-butyl perpivalate,t-amylperpivalate, bis(2,4-dichlorobenzoyl)peroxide, diisononanoylperoxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide,bis (2-methylbenzoyl) peroxide, disuccinic acid peroxide, diacetylperoxide, dibenzoyl peroxide, t-butyl per 2-ethylhexanoate,bis-(4-chlorobenzoyl)-peroxide, t-butyl perisobutyrate, t-butylpermaleinate, 1,1-bis(t-butylperoxy)3,5,5-trimethylcyclohexane,1,1-bis(t-butylperoxy)cyclohexane, t-butyl peroxy isopropyl carbonate,t-butyl perisononaoate, 2,5-dimethylhexane 2,5-dibenzoate, t-butylperacetate, t-amyl perbenzoate, t-butyl perbenzoate, 2,2-bis(t-butylperoxy) butane, 2,2 bis (t-butylperoxy) propane, dicumylperoxide, 2,5-dimethylhexane-2,5-di-t-butylperoxide, 3-t-butylperoxy3-phenylphthalide, di-t-amyl peroxide, α, α′-bis(t-butylperoxyisopropyl) benzene, 3,5-bis (t-butylperoxy)3,5-dimethyl 1,2-dioxolane,di-t-butyl peroxide, 2,5-dimethylhexyne-2,5-di-t-butylperoxide3,3,6,6,9,9-hexamethyl 1,2,4,5-tetraoxa cyclononane, p-menthanehydroperoxide, pinane hydroperoxide, diisopropylbenzenemono-α-hydroperoxide, cumene hydroperoxide or t-butyl hydroperoxide.

A suitable component a3) contains a compound of formula (III),

with a radically transferable atom or group .Hal as is described in WO96/30421 and WO 98/01480.

A preferred radically transferable atom or group .Hal is .Cl or .Br,which is cleaved as a radical from the initiator molecule.

Preferably [In] represents the polymerization initiator fragment of apolymerization initiator of formula (III),

capable of initiating polymerization of monomers or oligomers whichpolymerization initiator is selected from the group consisting ofC₁-C₈-alkyl halides, C₆-C₁₅-aralkylhalides, C₂-C₈α-haloalkyl esters,arene sulfonyl chlorides, haloalkane-nitriles, α-haloacrylates andhalolactones,

p and q represent one and the other components are as defined above.

The polymerization process in the presence of a compound of formula(III) is known as ATRP (Atom Transfer Radical Polymerization) and WO96/30421 discloses a controlled or “living” polymerization process ofethylenically unsaturated polymers such as styrene or (meth)acrylates byemploying the ATRP method. According to this method initiators areemployed which generate a radical atom such as .Cl, in the presence of aredox system of transition metals of different oxidation states, e.g.Cu(I) and Cu(II), providing “living” or controlled radicalpolymerization.

Specific initiators are selected from the group consisting ofα,α′-dichloro- or α,α′-dibromoxylene, p-toluenesulfonylchloride (PTS),hexakis-(α-chloro- or α-bromomethyl)-benzene, 2-chloro- or2-bromopropionic acid, 2-chloro- or 2-bromoisobutyric acid, 1-phenethylchloride or bromide, methyl or ethyl 2-chloro- or 2-bromopropionate,ethyl-2-bromo- or ethyl-2-chloroisobutyrate, chloro- orbromoacetonitrile, 2-chloro- or 2-bromopropionitrile,α-bromo-benz-acetonitrile and α-bromo-γ-butyrolactone(=2-bromo-dihydro-2(3H)-furanone).

The transition metal in the oxidizable transition metal complex catalystsalt used in the process of the invention is present as an oxidizablecomplex ion in the lower oxidation state of a redox system. Preferredexamples of such redox systems are selected from the group consisting ofGroup V(B), VI(B), VII(B), VIII, IB and IIB elements, such as Cu⁺/Cu²⁺,Cu⁰/Cu⁺, Fe⁰/Fe²⁺, Fe²⁺/Fe³⁺, Ru²⁺/Ru³⁺, Ru³⁺/Ru⁴⁺Os²⁺/Os³⁺,V^(n+)/V^((n+1)+), Cr²⁺/Cr³⁺, Co⁺/Co²⁺, Co²⁺/Co³⁺, Ni⁰/Ni⁺, Ni⁺/Ni²⁺,Ni²⁺/Ni³⁺, Mn⁰/Mn²⁺, Mn²⁺/Mn³⁺, Mn³⁺/Mn⁴⁺, or Zn⁺/Zn²⁺.

The ionic charges are counterbalanced by anionic ligands commonly knownin complex chemistry of transition metals, such hydride ions (H⁻) oranions derived from inorganic or organic acids, examples being halides,e.g. F⁻, Cl⁻, Br⁻ or I⁻, fluoro complexes of the type BF₄ ⁻, PF₆ ⁻, SbF₆⁻ or AsF₆ ⁻, anions of oxygen acids, alcoholates or acetylides or anionsof cyclopentadiene.

Anions of oxygen acids are, for example, sulfate, phosphate,perchlorate, perbromate, periodate, antimonate, arsenate, nitrate,carbonate, the anion of a C₁-C₈carboxylic acid, such as formate,acetate, propionate, butyrate, benzoate, phenylacetate, mono-, di- ortrichloro- or -fluoroacetate, sulfonates, for example methylsulfonate,ethylsulfonate, propylsulfonate, butylsulfonate,trifluoromethylsulfonate (triflate), unsubstituted or C₁-C₄alkyl-,C₁-C₄alkoxy- or halo-, especially fluoro-, chloro- or bromo-substitutedphenylsulfonate or benzylsulfonate, for example tosylate, mesylate,brosylate, p-methoxy- or p-ethoxyphenylsulfonate,pentafluorophenylsulfonate or 2,4,6-triisopropylsulfonate, phosphonates,for example methylphosphonate, ethylphosphonate, propylphosphonate,butylphosphonate, phenylphosphonate, p-methylphenylphosphonate orbenzylphosphonate, carboxylates derived from a C₁-C₈carboxylic acid, forexample formate, acetate, propionate, butyrate, benzoate, phenylacetate,mono-, di- or trichloro- or -fluoroacetate, and also C₁-C₁₂-alcoholates,such as straight chain or branched C₁-C₁₂-alcoholates, e.g. methanolateor ethanolate.

Anionic ligands and neutral may also be present up to the preferredcoordination number of the complex cation, especially four, five or six.Additional negative charges are counterbalanced by cations, especiallymonovalent cations such as Na⁺, K⁺, NH₄ ⁺ or (C₁-C₄ alkyl)₄N⁺.

Suitable neutral ligands are inorganic or organic neutral ligandscommonly known in complex chemistry of transition metals. Theycoordinate to the metal ion through a σ-, π-, μ-, η-type bonding or anycombinations thereof up to the preferred coordination number of thecomplex cation. Suitable inorganic ligands are selected from the groupconsisting of aquo (H₂O), amino, nitrogen, carbon monoxide and nitrosyl.Suitable organic ligands are selected from the group consisting ofphosphines, e.g. (C₆H₅)₃P, (i-C₃H₇)₃P, (C₅H₉)₃P or (C₆H₁₁)₃P, di-, tri-,tetra- and hydroxyamines, such as ethylenediamine,ethylenediaminotetraacetate (EDTA),N,N-Dimethyl-N′,N′-bis(2-dimethylaminoethyl)-ethylenediamine (Me₆TREN),catechol, N,N′-dimethyl-1,2-benzenediamine, 2-(methylamino)phenol,3-(methylamino)-2-butanol orN,N′-bis(1,1-dimethylethyl)-1,2-ethanediamine,N,N,N′,N″,N″-pentamethyldiethyltriamine (PMD-ETA), C₁-C₈-glycols orglycerides, e.g. ethylene or propylene glycol or derivatives thereof,e.g. di-, tri- or tetraglyme, and monodentate or bidentate heterocyclice⁻ donor ligands.

Heterocyclic e⁻ donor ligands are derived, for example, fromunsubstituted or substituted heteroarenes from the group consisting offuran, thiophene, pyrrole, pyridine, bis-pyridine, picolylimine,g-pyran, g-thiopyran, phenanthroline, pyrimidine, bis-pyrimidine,pyrazine, indole, coumarone, thionaphthene, carbazole, dibenzofuran,dibenzothiophene, pyrazole, imidazole, benzimidazole, oxazole, thiazole,bis-thiazole, isoxazole, isothiazole, quinoline, bis-quinoline,isoquinoline, bis-isoquinoline, acridine, chromene, phenazine,phenoxazine, phenothiazine, triazine, thianthrene, purine, bis-imidazoleand bis-oxazole.

The oxidizable transition metal complex catalyst can be formed in aseparate preliminary reaction step from its ligands or is preferablyformed in-situ from its transition metal salt, e.g. Cu(I)Cl, which isthen converted to the complex compound by addition of compoundscorresponding to the ligands present in the complex catalyst, e.g. byaddition of ethylenediamine, EDTA, Me₆TREN or PMDETA.

Preferred is a composition, wherein in the step a3) the oxidizabletransition metal in the transition metal complex salt is present as atransition metal complex ion in the lower oxidation state of a redoxsystem.

More preferred is a composition, wherein the transition metal complexion is a Cu(I) complex ion in the Cu(I)/Cu(II) system.

Typically a catalytically effective amount of the transition metal iondefines an amount of 0.001 to 20 mol %, particularly 0.001 to 2,0 mol %,and especially 0.01 to 1.0 mol %, based on the amount of monomer.

The initiator component is preferably present in an amount of 0.01 mol %to 30 mol %, more preferably in an amount of 0.1 mol % to 10 mol % andmost preferably in an amount of 0.1 to 5 mol %, based on the monomer,oligomer or monomer/oligomer mixture used.

It is also possible to carry out the first step as an anionicpolymerization (reaction a4). Anionic polymerizations are known and forexample described in Encyclopedia of Polymer Science and Technology,vol. 2, 1964, 95-137.

The anionic polymerization is for example carried out in an appropriateorganic solvent in the presence of an organic alkali metal compoundand/or an alkali metal as a polymerzation initiator at a temperature of−100° C. to 150° C. in the atomosphere of an inert gas such as nitrogenor argon.

Examples of polymerization initiators include alkali metals such aslithium, sodium and potassium; and/or organic alkali metal compoundssuch as ethyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyllithium, butadienyl dilithium, butadienyl disodium, lithium biphenylide,sodium biphenylide, lithium di-tert-butylbiphenylide, sodiumdi-tert-butylbiphenylide, lithium naphthalenide, sodium naphthalenide,lithium triphenylide, sodium triphenylide, α-methylstyrenesodium anionradical, 1,1-diphenyl hexyl lithium, and 1,1-diphenyl-3-methylpentyllithium.

The polymerization is typically carried out in a solvent. Solvents are,for example, aliphatic hydrocarbons such as n-hexane and n-heptane;alicyclic hydrocarbons such as cyclohexane and cyclopentane; aromatichydrocarbons such as benzene and toluene; aliphatic ethers such asdiethyl ether; cyclic ethers such as tetrahedrofuran and dioxane; andthe like.

The polymerization process according to step a1) is in generalpreferred.

A very suitable process is, wherein the nitroxyl ether of formula

is used in the polymerization step a1).

Preferably the optionally used additional ethylenically unsaturatedmonomer is selected from the group consisting of an acrylic acid ester,acrylamide, acryinitrile, methacrylic acid ester, methacrylamide,methacryinitrile and styrene.

Acrylic acid esters and methacrylic acid esters are typicallyC₁-C₁₈alkyl esters.

Such an additional monomer is preferably used in an amount of 1 part to30 parts based on 100 parts of hydroxy functional vinyl aromaticmonomer.

Most preferred is n-butylacrylate, tert-butylacrylate, methylacrylate,ethylacrylate, propylacrylate, hexylacrylate, hydroxyethylacrylate andstyrene.

Preferably the nitroxylether of step a1) or the nitroxyl radical of stepa2) is present in an amount of from 0.001 mol-% to 20 mol-%, morepreferably of from 0.002 mol-% to 10 mol-% and most preferably of from0.005 mol-% to 5 mol-% based on the monomer or monomer mixture.

Preferably the free radical initiator is present in an amount of 0.001mol-% to 20 mol-%, based on the monomer or monomer mixture.

The molar ratio of free radical initiator to stable free nitroxylradical is preferably from 20:1 to 1:2, more preferably from 10:1 to1:2.

Scission of the O—X bond of the nitroxylether may be effected byultrasonic treatment, radiation with actinic light or heating.

The scission of the O—X bond is preferably effected by heating and takesplace at a temperature of between 50° C. and 180° C., more preferablyfrom 190° C. to 150° C.

Consequently the polymerization temperature in the steps a1), a2) or a3)is between 90° C. and 150° C.

The polymerization reaction is carried out with preference underatmospheric pressure.

Preferably the hydroxy-vinyl aromatic oligomer, cooligomer, polymer orcopolymer has a weight molecular weight average from 2000 to 30 000Daltons.

Preferably the hydroxy-vinyl aromatic oligomer, cooligomer, polymer orcopolymer has a polydispersity M_(w)/M_(n) of between 1.1 and 1.8, inparticular between 1.1 and 1.6.

After the polymerization step is completed the reaction mixture may becooled down to a temperature below 60° C., preferably to roomtemperature. The polymer may be stored at this temperature withoutfurther reactions occurring.

The radical polymerization process may be carried out in bulk, in thepresence of an organic solvent or in the presence of water or inmixtures of organic solvents and water. Additional cosolvents orsurfactants, such as glycols or ammonium salts of fatty acids, may bepresent. Other suitable cosolvents are described hereinafter.

If organic solvents are used, suitable solvents or mixtures of solventsare typically pure alkanes (hexane, heptane, octane, isooctane),aromatic hydrocarbons (benzene, toluene, xylene), halogenatedhydrocarbons (chlorobenzene), alkanols (methanol, ethanol, ethyleneglycol, ethylene glycol monomethyl ether), esters (ethyl acetate,propyl, butyl or hexyl acetate) and ethers (diethyl ether, dibutylether, ethylene glycol dimethyl ether), anisol, or mixtures thereof.

The aqueous polymerization reactions can be supplemented with awater-miscible or hydrophilic cosolvent to help ensure that the reactionmixture remains a homogeneous single phase throughout the monomerconversion. Any water-soluble or water-miscible cosolvent may be used,as long as the aqueous solvent medium is effective in providing asolvent system which prevents precipitation or phase separation of thereactants or polymer products until after all polymerization reactionshave been completed. Exemplary cosolvents useful in the presentinvention may be selected from the group consisting of aliphaticalcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkylpyrrolidinones, N-alkyl pyrrolidones, polyethylene glycols,polypropylene glycols, amides, carboxylic acids and salts thereof,esters, organosulfides, sulfoxides, sulfones, alcohol derivatives,hydroxyether derivatives such as butyl carbitol or cellosolve, aminoalcohols, ketones, and the like, as well as derivatives thereof andmixtures thereof. Specific examples include methanol, ethanol, propanol,dioxane, ethylene glycol, propylene glycol, diethylene glycol, glycerol,dipropylene glycol, tetrahydrofuran, and other water-soluble orwater-miscible materials, and mixtures thereof. When mixtures of waterand water-soluble or water-miscible organic liquids are selected as theaqueous reaction media, the water to cosolvent weight ratio is typicallyin the range of about 100:0 to about 10:90.

At the end of polymerization step, the reaction mixture may beoptionally treated with a hydrogen donor like phenol, hydroquinone,catechol, thiol and hydroxylamine at a temperature between 50° C. and180° C. or with a peracid to remove the terminal nitroxyl group asdescribed in Macromol. Chem. Phys. 199, 583 (1998) or JP2000-026535.

The protective group R₄ is removed in a reaction with an halosilanereagent, step b). This type of reaction is in principal known.

In a specific embodiment of the invention the halosilane reagent of stepb) is R₁₃R₁₄R₁₅SiX, wherein R₁₃, R₁₄ and R₁₅ are independentlyC₁-C₈alkyl, chloromethyl, vinyl or phenyl and X is Cl, Br or I.

In one preferred embodiment X is I.

The reaction is usually carried out under atmospheric pressure at atemperature from 10° C. to 150° C., preferably from 30° C. to 100° C.

In a specific embodiment of the invention the process of step b), thereaction with an halosilane reagent, is carried out using a chlorosilanereagent from R₁₃R₁₄R₁₅SiCl wherein R₁₃, R₁₄ and R₁₅ are independentlyC₁-C₈alkyl, chloromethyl, vinyl or phenyl in the presence of halide saltand/or thiol, wherein the halide salt is selected from the groupconsisting of alkaline metal halide, alkaline-earth metal halide,ammonium halide or phosphonium halide.

For example the halide salt is a bromide or iodide salt.

For instance the molar ratio of halide salt to chlorosilane is from 1:50to 2:1.

In one embodiment of the invention the reaction with an iodosilanereagent is carried out by in situ generation of iodotrimethylsilaneusing chlorotrimethylsilane and sodium iodide as described in J. Org.Chem., 44(8), 1247, 1979.

In another specific embodiment of the invention the monomer is4-tert.-butoxystyrene or 4-benzyloxystyrene, the polymerization step iscarried out according to step a1 using2,6-diethyl-2,3,6-trimethyl-1-(1-phenyl-ethoxy)-piperidine-4-one oxime,optionally followed by treating the polymer with thioglycolic acid,2-ethylhexylthioglycolate or thiosalicylic acid at a temperature between130 and 145° C. In the deprotection step b) the halosilane ischlorotrimethylsilane and the halide salt is NaI, Kl or NaBr. The Thiolis thioglycolic acid or 2-ethylhexylthioglycolate. The deprotection ispreferably carried out in a solvent, such as 2-butanone, acetonitrileorethyacetate at a temperature from 20° C. to 80° C.

The hydroxy-vinyl-aromatic polymer with low polydispersity preparedaccording to the present invention is particularly useful as bindermaterial for negative or positive working photoresists. It's main usehowever is in positive photo resists. The formulation of such resists isknown to those skilled in the art and for example described in EP 813113 or EP 488 748.

Consequently a further aspect of the invention is a formulatedphotoresist prepared from a polymer obtainable by a process as describedabove.

The following examples illustrate the invention.

Preparation of2,6-Diethyl-2,3,6-trimethyl-1-(1-phenyl-ethoxy)-piperidine-4-one oxime(Compound 1 According to WO 02/100831)

2,6-diethyl-2,3,6-trimethyl-1-(1-phenyl-ethoxy)-4-oxopiperidine preparedaccording to DE 199 09 767 A1 is dissolved in methanol containing 10% byweight of KOH and stirred for 5 hours at room temperature. Methanol isevaporated, the residue is washed with water and dried in vacuo. Asolution of 95.24 g (0.3 mol) of2,6-diethyl-2,3,6-trimethyl-1-(1-phenyl-ethoxy)-4-oxopiperidine and 29.7g (0.45 mol) 50% aqueous hydroxylamine solution in 150 ml of methanol isstirred under reflux during 5 h. The suspension is then cooled to −8° C.and filtered. The solid is washed with 100 ml of a cold (−20° C.)methanol and dried to afford 64 g (64.1%) of the title compound as awhite, microcrystalline powder, mp 130-145 oC. C₂₀H₃₂N₂O₂ (332.49)calculated C 72.25%, H 9.70%, N 8.43%; found 72.19% C, 9.54% H, 8.43% N.

A) Preparation of Polymers

EXAMPLE A1

4-Benzyloxystyrene (10.5 g, 50.0 mmol) and compound 1 (0.223 g, 0.667mmol) are placed in a 100 mL schlenk tube and degassed, followed bypurging with Ar. The mixture is heated to 130° C. and stirred for 6 hunder Ar. The reaction mixture is cooled down to room temperature anddissolved in CH₂C₁₂ (15 mL). The polymer is precipitated in MeOH (300mL) and washed with MeOH. The precipitation is repeated twice, and 7.17g of white solid are obtained after drying in a vacuum oven overnight.GPC analysis using tetrahydrofuran (THF) as mobile phase and calibrationwith polystyrene standard shows Mn=7723, Mw/Mn=l1.19. ¹H NMR (CDCl₃):0.7-2.4 (br m), 4.9 (br s), 6.0-6.9 (br m), 6.9-7.6 (br m).

EXAMPLE A2

4-t-Butoxystyrene (17.6 g, 100 mmol) and the compound (1) (0.555 g, 1.67mmol) are placed in a 100-mL schlenk tube and degassed, followed bypurging with Ar. The mixture is heated to 130° C. and stirred for 8 hunder Ar. The reaction mixture is cooled down to room temperature anddissolved in EtOAc (15 mL). The polymer is purified by repeatedprecipitation from MeOH (150 mL). 14.1 g of white solid are obtainedafter drying in a vacuum oven overnight. GPC analysis using THF asmobile phase and calibration with polystyrene standard shows Mn=7970,Mw/Mn=1.10. ¹H NMR (CDCl₃): 0.8-2.4 (br m), 6.1-7.2 (br m).

EXAMPLE A3

4-t-Butoxystyrene (17.6 g, 100 mmol), the compound (1) (0.55 g, 1.67mmol) and p-xylene (2.48 g) are placed in a 50-mL test tube anddegassed, followed by purging with N₂. The mixture is heated to 130° C.and stirred for 15 h under N₂. 12.6 g of white solid are obtained afterthe same work-up as described in example A2. Mn=8070, Mw/Mn=1.13.

EXAMPLE A4

4-t-Butoxystyrene (584 g, 3.31 mol), the compound (1) (12.3 g, 37.0mmol) and butyl acetate (64.9 g) are placed in a 1-L flask, and theinner gas is replaced with N₂. The mixture is heated to 125-135° C. andstirred for 24 h under N₂. 527 g of white solid are obtained afterprecipitation from MeOH. Mn=13140, Mw/Mn=1.11.

EXAMPLE A5

4-t-Butoxystyrene (17.7 g, 101 mmol), the compound (1) (0.348 g, 1.05mmol) and butyl acetate (2.13 g) are placed in a 50-mL test tube, andthe inner gas is replaced with N₂. The mixture is heated to 125° C. andstirred for 25 h under N₂. 15.4 g of white solid are obtained after thesame work-up as described in example A2. Mn=14530, Mw/Mn=1.08.

EXAMPLE A6

4-t-Butoxystyrene (441 g, 2.50 mol), the compound (1) (4.75 g, 14.3mmol) and butyl acetate (49 g) are placed in a 1-L 3-necked flask, andthe inner gas is replaced with N₂. The mixture is heated to 125-135° C.and stirred for 24 h under N₂. 493 g of white solid are obtained afterrepeated precipitation from MeOH. Mn=21920, Mw/Mn=1.14.

EXAMPLE A7

4-t-Butoxystyrene (17.7 g, 101 mmol), the compound (1) (0.475 g, 1.43mmol) and butyl acetate (1.98 g) are placed in a 50-mL test tube, andthe inner gas is replaced with N₂. The mixture is heated to 130° C. andstirred for 24 h under N₂. After cooling down to room temperature,4,4′-thiobis(6-tert-butyl-m-cresol) (2.05 g, 5.71 mmol) is added, andthe reaction mixture are heated at 130° C. for 4 h after replacing theinner gas with N₂. 14.3 g of white solid are obtained after the samework-up as described in example A2. Mn=9120, Mw/Mn=1.09.

EXAMPLE A8

4-t-Butoxystyrene (17.7 g, 101 mmol), the compound (1) (0.444 g, 1.34mmol) and butyl acetate (2.00 g) are placed in a 50-mL test tube, andthe inner gas is replaced with N₂. The mixture is heated to 130° C. andstirred for 29 h under N₂. After cooling down to room temperature,4,4′-Thiobis(6-tert-butyl-m-cresol) (0.96 g, 2.68 mmol) and butylacetate (2 mL) are added, and the reaction mixture are heated at 130° C.for 4 h after replacing the inner gas with N₂. 15.8 g of white solid areobtained after the same work-up as described in example A2. Mn=10070,Mw/Mn=1.10.

EXAMPLE A9

4-t-Butoxystyrene (1.06 kg, 6.00 mol), the compound (1) (25.0 g, 75.2mmol) and butyl acetate (118 g) are placed in a 2-L 3-necked flask, andthe inner gas is replaced with N₂. The mixture is heated to 125-135° C.and stirred for 24 h under N₂. After cooling down to room temperature,thioglyclic acid (55.3 g, 600 mmol) and butyl acetate (250 mL) areadded, and the reaction mixture are heated at 140° C. for 16 h afterreplacing the inner gas with N₂. 888 g of white solid are obtained afterrepeated precipitation from MeOH. Mn=11140, Mw/Mn=1.06.

EXAMPLE A10

4-t-Butoxystyrene (17.6 g, 100 mmol), the compound (1) (0.372 g, 1.12mmol) and butyl acetate (2.19 g) are a 50-mL test tube, and the innergas is replaced with N₂. The mixture is heated to 130° C. and stirredfor 24 h under N₂. 2.05 g of the reaction mixture and thiosalicylic acid(0.184 g, 1.19 mmol) are dissolved in 2.0 mL of butyl acetate. Thismixture is heated at 130° C. for 15 h. The polymer is dissolved in ethylacetate and washed with K₂CO₃ aq. solution. After condensation, thepolymer is precipitated from 5% aqueous MeOH (50 mL). 1.39 g of paleyellow solid is collected. Mn=11440, Mw/Mn=1.08.

EXAMPLE A11

4-t-Butoxystyrene (17.7 g, 101 mmol), the compound (1) (0.224 g, 0.674mmol) and butyl acetate (2.01 g) are placed in a 50-mL test tube, andthe inner gas is replaced with N₂. The mixture is heated to 130° C. andstirred for 29 h under N₂. After cooling down to room temperature,4,4′-thiobis(6-tert-butyl-m-cresol) (0.49 g, 1.37 mmol) and butylacetate (2 mL) are added, and the reaction mixture are heated at 130° C.for 4 h after replacing the inner gas with N₂. 15.5 g of white solid areobtained after the same work-up as described in example A2. Mn=17950,Mw/Mn=1.13.

EXAMPLE A12

4-t-Butoxystyrene (17.6 g, 100 mmol), the compound (1) (0.172 g, 0.517mmol) and butyl acetate (1.97 g) are placed in a 50-mL test tube, andthe inner gas is replaced with N₂. The mixture is heated to 130° C. andstirred for 24 h under N₂. After cooling down to room temperature,4,4′-thiobis(6-tert-butyl-m-cresol) (0.74 g, 2.06 mmol) is added, andthe reaction mixture are heated at 130° C. for 4 h after replacing theinner gas with N₂. 14.4 g of white solid are obtained after the samework-up as described in example A2. Mn=23080, Mw/Mn=1.12.

EXAMPLE A13

The polymer prepared in example A6 (142.9 g) and 2-ethylhexylthioglycolate (14.6 g, 71.3 mmol) are placed in a 500-mL flask, and theinner gas is replaced with N₂. The mixture is heated at 130° C. for 20 hunder N₂. 138.9 g of white solid are obtained after the same work-up asdescribed in example A2. Mn=23080, Mw/Mn=1.12.

EXAMPLE A14

4-t-Butoxystyrene (17.6 g, 100 mmol), styrene (1.85 g, 17.8 mmol) andthe compound (1) (0.392 g, 1.18 mmol) are placed in a 50-mL test tube,and the inner gas is replaced with N₂. The mixture is heated to 130° C.and stirred for 8 h under N₂. 15.0 g of white solid are obtained afterthe same work-up as described in example A2. Mn=11300, Mw/Mn=1.06. ¹HNMR (CDCl₃): 0.8-2.4 (br m), 6.1-7.2 (br m). The polymer is identifiedby ¹H NMR as copolymer of 4-t-butoxystyrene and styrene, and the molarratio is estimated to be 90:10.

EXAMPLE A15

The polymer prepared in example A14 (5.01 g), thioglycolic acid (0.240g, 2.61 mmol) and butyl acetate (3.0 mL) are placed in a 30-mL flask,and the inner gas is replaced with N₂. The mixture is heated at 130° C.for 18.5 h under N₂. 4.53 g of white solid are obtained by precipitationfrom MeOH (100 mL) and H₂O (10 mL). Mn=11240, Mw/Mn=1.07.

B) Deprotection

EXAMPLE B1

1.02 g of poly(4-benzyloxystyrene), prepared in example A1, 1.52 g ofsodium iodide, 1.3 mL of chlorotrimethylsilane and 5.0 mL ofacetonitrile are placed in a 30 mL round bottom flask. After heating at80° C. for 3 hours, sodium thiosulfate aqueous solution and ethylacetate are added. The organic layer is washed with water and thenbrine, followed by drying over anhydrous MgSO4. After condensation, theresulting solid is dissolved in 10 mL of MeOH and precipitated inCH₂C₂/hexane (1:1, 200 mL), followed by washing with this solventmixture. 0.58 g of a white solid are obtained after drying in a vacuumoven overnight. GPC analysis using DMF including LiBr as mobile phaseand calibration with polystyrene standard shows Mn=22744, Mw/Mn=1.25. ¹HNMR shows the disappearance of the benzylic protons. Transmittance at248 nm of the polymer is 70% in EtOH at 0.1 g/L concentration (celllength: 1 cm). ¹H NMR (DMSO-d6): 0.6-2.0 (br m, 3 H), 5.9-6.8 (br m, 4H), 9.0 (br s, 1 H).

EXAMPLE B2

1.00 g of poly(4-t-butoxystyrene), prepared in example A3 and 10.0 mL ofacetonitrile are placed in a 30-mL 3-necked flask. To this solution areadded NaI (0.79 g, 5.3 mmol) and chlorotrimethylsilane (0.54 g, 5.0mmol) at room temperature. The mixture is stirred under reflux for 3 h.After adding 10% sodium thiosulfate aq. solution (15 mL), polymer isextracted with ethyl acetate (25 mL). The ethyl acetate layer is washedwith water and brine, followed by drying over anhydrous Na₂SO₄. Aftercondensation 0.72 g of white solid is obtained. Mn=7240, Mw/Mn=1.20.

EXAMPLE B3

1.00 g of poly(4-t-butoxystyrene), prepared in example A7, is dissolvedin 3.0 mL of acetonitrile and 3.0 mL of ethyl acetate. To this solutionare added NaI (1.04 g, 7.0 mmol) and chlorotrimethylsilane (0.79 g, 7.4mmol) at room temperature. The mixture is stirred at room temperaturefor 18 h. After the same work up as described in Example B2, 0.67 g ofwhite solid is obtained. Mn=8440, Mw/Mn=1.15.

EXAMPLE B4

1.00 g of poly(4-t-butoxystyrene), prepared in example A8, is dissolvedin 10.0 mL of acetonitrile. To this solution are added NaI (1.06 g, 7.1mmol) and chlorotrimethylsilane (0.76 g, 7.0 mmol) at room temperature.The mixture is stirred at room temperature for 18 h. After the same workup as described in Example B2, 0.74 g of white solid is obtained.Mn=9720, Mw/Mn=1.11.

EXAMPLE B5

737 g of poly(4-t-butoxystyrene), prepared in example A9, and 774 g(5.16 mol) of NaI and 5.2 L of ethyl acetate are placed in a 20-Lseparable flask. To this solution is added dropwisechlorotrimethylsilane (561 g, 5.16 mol) at room temperature. The mixtureis stirred at room temperature for 2.5 h. 10% ascorbic acid aqueoussolution is added and the organic layer is repeatedly washed with 10%ascorbic acid aqueous solution, water and brine, followed by drying overanhydrous Na₂SO₄. After condensation the residue is dissolved in MeOH,and precipitation from water afforded 517 g of white solid. Mn=9950,Mw/Mn=1.06. This polymer showed 75% of transmittance at 248 nm (at 0.1g/L in EtOH, 1 cm-cell).

EXAMPLE B6

450 g of poly(4-t-butoxystyrene), prepared in example A4, and 450 g(3.00 mol) of NaI and 1.4 L of ethyl acetate are placed in a 5-Lseparable flask. To this solution is added dropwisechlorotrimethylsilane (333 g, 3.07 mol) at room temperature. The mixtureis stirred at room temperature for 2.5 h. After the same work up asdescribed in Example B5, 363 g of white solid is obtained. Mn=11700,Mw/Mn=1.16.

EXAMPLE B7

1.00 g of poly(4-t-butoxystyrene), prepared in example A10, is dissolvedin 3.0 mL of acetonitrile and 3.0 mL of ethyl acetate. To this solutionare added NaI (1.05 g, 7.0 mmol) and chlorotrimethylsilane (0.90 mL, 7.1mmol) at room temperature. The mixture is stirred at room temperaturefor 15 h. After the same work up as described in Example B2, 0.71 g ofwhite solid is obtained. Mn=9960, Mw/Mn=1.09.

EXAMPLE B8

1.00 g of poly(4-t-butoxystyrene), prepared in example A11, is dissolvedin 10.0 mL of acetonitrile. To this solution are added NaI (1.06 g, 7.1mmol) and chlorotrimethylsilane (0.82 g, 7.5 mmol) at room temperature.The mixture is stirred at room temperature for 19.5 h. After the samework up as described in Example B2, 0.73 g of white solid is obtained.Mn=15890, Mw/Mn=1.15.

EXAMPLE B9

1.00 g of poly(4-t-butoxystyrene), prepared in example A12, is dissolvedin 3.0 mL of acetonitrile and 3.0 mL of ethyl acetate. To this solutionare added NaI (1.05 g, 7.0 mmol) and chlorotrimethylsilane (0.79 g, 7.3mmol) at room temperature. The mixture is stirred at room temperaturefor 18 h. After the same work up as described in Example B2, 0.68 g ofwhite solid is obtained. Mn=21660, Mw/Mn=1.20.

EXAMPLE B10

1.00 g of poly(4-t-butoxystyrene), prepared in example A6, is dissolvedin 6.0 mL of 2-butanone. To this solution are added NaI (0.090 g, 0.60mmol) and chlorotrimethylsilane (0.65 g, 6.0 mmol) at room temperature.The mixture is stirred at 50° C. for 18 h, and then MeOH is added.Precipitation from H₂O afforded 0.59 g of white solid. Mn=20220,Mw/Mn=1.16.

EXAMPLE B11

1.02 g of poly(4-t-butoxystyrene), prepared in example A6, is dissolvedin 3.0 mL of 2-butanone. To this solution are added NaI (0.098 g, 0.65mmol), 2-ethylhexylthioglycolate (0.15 mL, 0.72 mmol) and thenchlorotrimethylsilane (0.80 mL, 6.3 mmol) at room temperature. Themixture is stirred at 80° C. for 3.5 h. After the same work up asdescribed in Example B10, 0.62 g of white solid is obtained. Mn=19350,Mw/Mn=1.14.

EXAMPLE B12

1.00 g of poly(4-t-butoxystyrene), prepared in example A6, is dissolvedin 6.0 mL of 2-butanone. To this solution are added KBr (0.73 g, 6.1mmol), 2-ethylhexylthioglycolate (1.30 mL, 6.20 mmol) and thenchlorotrimethylsilane (0.68 mL, 6.2 mmol) at room temperature. Themixture is stirred at 50° C. for 3.5 h. After the same work up asdescribed in Example B10, 0.65 g of white solid is obtained. Mn=19300,Mw/Mn=1.13.

EXAMPLE B13

1.03 g of poly(4-t-butoxystyrene), prepared in example A6, is dissolvedin 6.0 mL of 2-butanone. To this solution are added NaCl (0.36 g, 6.1mmol) and chlorotrimethylsilane (0.80 mL, 6.3 mmol) at room temperature.The mixture is stirred at 80° C. for 20 h. After the same work up asdescribed in Example B10, 0.61 g of white solid is obtained. Mn=19290,Mw/Mn=1.17.

EXAMPLE B14

1.03 g of poly(4-t-butoxystyrene), prepared in example A6, is dissolvedin 6.0 mL of 2-butanone. To this solution are added2-ethylhexylthioglycolate (1.30 mL, 6.20 mmol) and chlorotrimethylsilane(0.67 g, 6.2 mmol) at room temperature. The mixture is stirred at 50° C.for 6.5 h, and then MeOH is added. After precipitation from hexane, 0.34g of white solid is obtained. Mn=19460, Mw/Mn=1.13.

EXAMPLE B15

10.0 g of poly(4-t-butoxystyrene), prepared in example A13, is dissolvedin 30.0 mL of 2-butanone. To this solution are added NaI (0.90 g, 6.00mmol) and chlorotrimethylsilane (7.60 mL, 59.9 mmol) at roomtemperature. The mixture is stirred at 80° C. for 3.5 h, and then MeOHis added. After precipitation from H₂O, 6.41 g of white solid isobtained. Mn=19070, Mw/Mn=1.13.

EXAMPLE B16

The polymer prepared in example A15 (1.08 g) is dissolved in ethylacetate (7.0 mL). To this solution are added NaI (1.06 g, 6.98 mmol) andchlorotrimethylsilane (1.01 g, 9.29 mmol) at room temperature. Themixture is stirred for 4 h. After adding 10% ascorbic acid aq. solution,polymer is extracted with ethyl acetate. The ethyl acetate layer iswashed with water and brine, followed by drying over anhydrous Na₂SO₄.After condensation 0.86 g of yellow solid is obtained. Mn=10360,Mw/Mn=1.07. ¹H NMR (DMSO-d₆): 0.7-2.2 (br m), 5.9-6.8 (br m), 6.8-7.3(br m), 8.7-9.1 (br s).

1. A process for the preparation of a narrow molecular weightdistributed hydroxy-vinyl aromatic oligomer, cooligomer, polymer orcopolymer with a polydispersity M_(w)/M_(n) between 1 and 2, whichprocess comprises the steps reacting a composition of at least onemonomer of formula I

wherein R₁ is H or CH₃; R₂ and R₃ are independently hydrogen,C₁-C₈alkyl, C₁-C₈alkoxy, C₁-C₈alkoxycarbonyl, C₁-C₈alkylthio,C₁-C₈dialkylamino, trihalogenmethyl; R₄ is C₁-C₁₂alkyl or benzyl whichis unsubstituted or substituted with one or two C₁-C₈alkyl, C₁-C₈alkoxy,C₁-C₈alkoxycarbonyl, C₁-C₈alkylthio, C₁-C₈dialkylamino,trihalogenmethyl, halogen; or R₄ is a group phenyl(methyl)CH—,(phenyl)₂CH—, C₁-C₁₂alkyl-O—C(O)—, phenyl-CH₂—O—C(O)— or(phenyl)₂CH—O—C(O)—; a1) in the presence of at least one nitroxyletherhaving the structural element

wherein X represents a group having at least one carbon atom and is suchthat the free radical X. derived from X is capable of initiatingpolymerization of ethylenically unsaturated monomers; or a2) in thepresence of at least one stable free nitroxyl radical

and a free radical initiator; or a3) in the presence of a compound offormula (III)

and a catalytically effective amount of an oxidizable transition metalcomplex catalyst, wherein p represents a number greater than zero anddefines the number of initiator fragments; q represents a number greaterthan zero; [ln] represents a radically transferable atom or groupcapable of initiating polymerization and —[Hal] represents a leavinggroup; or a4) in an anionic polymerization reaction in the presence of ametal or organo metal catalyst; and optionally simultaneously or in asubsequent step with one or more ethylenically unsaturated monomersdifferent from those of formula (I); and b) isolating the resultingpolymer and subjecting it to a reaction with a halosilane giving apolymer with repeating units of formula II

and with a degree of OH-groups of between 10 mol % and 100 mol %, basedon the molar amount of protected hydroxy-vinyl aromatic monomer offormula I.
 2. A process according to claim 1 wherein halosilane isiodosilane.
 3. A process according to claim 1 wherein the polymerizationis carried out according to steps a1) or a2).
 4. A process according toclaim 1 wherein in formula I R₁ is H; R₂ and R₃ are H; OR₄ is in the4-position and R₄ is C₁-C₄alkyl, benzyl, C₁-C₄alkoxycarbonyl orbenzyloxycarbonyl.
 5. A process according to claim 1, wherein thenitroxylether in step a1) is of formula A, B or O,

wherein m is 1, R is hydrogen, C₁-C₁₈alkyl which is uninterrupted orinterrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl,a monovalent radical of an aliphatic carboxylic acid having 2 to 18carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbonatoms, or an α,β-unsaturated carboxylic acid having 3 to 5 carbon atomsor of an aromatic carboxylic acid having 7 to 15 carbon atoms; p is 1;R₁₀₁ is C₁-C₁₂alkyl, C₅-C₇cycloalkyl, C₇-C₈aralkyl, C₂-C₁₈alkanoyl,C₃-C₅alkenoyl or benzoyl; R₁₀₂ is C₁-C₁₈alkyl, C₅-C₇cycloalkyl,C₂-C₈alkenyl unsubstituted or substituted by a cyano, carbonyl orcarbamide group, or is glycidyl, a group of the formula —CH₂CH(OH)-Z orof the formula —CO-Z or —CONH-Z wherein Z is hydrogen, methyl or phenyl;G₆ is hydrogen and G₅ is hydrogen or C₁-C₄alkyl, G₁ and G₃ are methyland G₂ and G₄ are ethyl or propyl or G₁ and G₂ are methyl and G₃ and G₄are ethyl or propyl; and X is selected from the group consisting of—CH₂-phenyl, CH₃CH-phenyl, (CH₃)₂C-phenyl, (C₅-C₆cycloalkyl)₂CCN,(CH₃)₂CCN,

—CH₂CH═CH₂, CH₃CH—CH═CH₂ (C₁-C₄alkyl)CR₂₀—C(O)-phenyl,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkoxy,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—N-di(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—NH(C₁-C₄)alkyl, (C₁-C₄)alkyl-CR₂₀—C(O)—NH₂,wherein R₂₀ is hydrogen or (C₁-C₄)alkyl.
 6. A process according to claim1, wherein the nitroxylether of step a1) is of formula (Ic), (Id), (Ie),(If), (Ig) or (Ih)

wherein R₂₀₁, R₂₀₂, R₂₀₃ and R₂₀₄ independently of each other areC₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl, C₁-C₁₈alkyl, C₃-C₁₈alkenyl,C₃-C₁₈alkinyl which are substituted by OH, halogen or a group—O—C(O)—R₂₀₅, C₂-C₁₈alkyl which is interrupted by at least one O atomand/or NR₂₀₅ group, C₃-C₁₂cycloalkyl or C₆-C₁₀aryl or R₂₀₁ and R₂₀₂and/or R₂₀₃ and R₂₀₄ together with the linking carbon atom form aC₃-C₁₂cycloalkyl radical; R₂₀₅ , R₂₀₆ and R₂₀₇ independently arehydrogen, C₁-C₁₈alkyl or C₆-C₁₀aryl; R₂₀₈ is hydrogen, OH, C₁-C₁₈alkyl,C₃-C₁₈alkenyl, C₃-C₁₈alkinyl, C₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₈alkinylwhich are substituted by one or more OH, halogen or a group—O—C(O)—R₂₀₅, C₂-C₁₈alkyl which is interrupted by at least one O atomand/or NR₂₀₅ group, C₃-C₁₂cycloalkyl or C₆-C₁₀aryl, C₇-C₉phenylalkyl,C₅-C₁₀heteroaryl, —C(O)—C₁-C₁₈alkyl, —O—C₁-C₁₈alkyl or —COOC₁-C₁₈alkyl;R₂₀₉, R₂₁₀, R₂₁₁ and R₂₁₂ are independently hydrogen, phenyl orC₁-C₁₈alkyl; and X is selected from the group consisting of —CH₂-phenyl,CH₃CH-phenyl, (CH₃)₂C-phenyl, (C₅-C₆cycloakyl)₂CCN, (CH₃)₂CCN,

—CH₂CH═CH₂, CH₃CH—CH═CH₂ (C₁-C₄alkyl)CR₂₀—C(O)-phenyl,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkoxy,(C₁-C₄)alkyl-CR₂₀—C(O)—(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—N-di(C₁-C₄)alkyl,(C₁-C₄)alkyl-CR₂₀—C(O)—NH(C₁-C₄)alkyl, (C₁-C₄)alkyl-CR₂₀—C(O)—NH₂,wherein R₂₀ is hydrogen or (C₁-C₄)alkyl.
 7. A process according to claim1, wherein the nitroxyl radical of step a2) is of formula A′, B′ or O′,

wherein m is 1, R is hydrogen, C₁-C₁₈alkyl which is uninterrupted orinterrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl,a monovalent radical of an aliphatic carboxylic acid having 2 to 18carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbonatoms, or an α,β-unsaturated carboxylic acid having 3 to 5 carbon atomsor of an aromatic carboxylic acid having 7 to 15 carbon atoms; p is 1;R₁₀₁ is C₁-C₁₂alkyl, C₅-C₇cycloalkyl, C₇-C₈aralkyl, C₂-C₁₈alkenoyl,C₃-C₅alkenoyl or benzoyl; R₁₀₂ is C₁-C₁₈alkyl, C₅-C₇cycloalkyl,C₂-C₈alkenyl unsubstituted or substituted by a cyano, carbonyl orcarbamide group, or is glycidyl, a group of the formula —CH₂CH(OH)-Z orof the formula —CO-Z or —CONH-Z wherein Z is hydrogen, methyl or phenyl;G₆ is hydrogen and G₅ is hydrogen or C₁-C₄alkyl, and G₁ and G₃ aremethyl and G₂ and G₄ are ethyl or propyl or G₁ and G₂ are methyl and G₃and G₄ are ethyl or propyl.
 8. A process according to claim 1, whereinthe nitroxyl radical of step a2) is of formula (Ic′), (Id′), (Ie′),(If′), (Ig′) or (Ih′)

wherein R₂₀₁, R₂₀₂, R₂₀₃ and R₂₀₄ independently of each other areC₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinyl, C₁-C₁₈alkyl, C₃-C₁₈alkenyl,C₃-C₁₈alkinyl which are substituted by OH, halogen or a group—O—C(O)—R₂₀₅, C₂-C₁₈alkyl which is interrupted by at least one O atomand/or NR₂₀₅ group, C₃-C₁₂cycloalkyl or C₆-C₁₀aryl or R₂₀₁ and R₂₀₂and/or R₂₀₃ and R₂₀₄ together with the linking carbon atom form aC₃-C₁₂cycloalkyl radical; R₂₀₅, R₂₀₆ and R₂₀₇ independently arehydrogen, C₁-C₁₈alkyl or C₆-C₁₀aryl; R₂₀₈ is hydrogen, OH, C₁-C₁₈alkyl,C₃-C₁₈alkenyl, C₃-C₁₈alkinyl, C₁-C₁₈alkyl, C₃-C₁₈alkenyl, C₃-C₁₈alkinylwhich are substituted by one or more OH, halogen or a group—O—C(O)—R₂₀₅, C₂-C₁₈alkyl which is interrupted by at least one O atomand/or NR₂₀₅ group, C₃-C₁₂cycloalkyl or C₆-C₁₀aryl, C₇-C₉phenylalkyl,C₅-C₁₀heteroaryl, —C(O)—C₁-C₁₈alkyl, —O—C₁-C₁₈alkyl or —COOC₁-C₁₈alkyl;and R₂₀₉, R₂₁₀, R₂₁₁ and R₂₁₂ are independently hydrogen, phenyl orC₁-C₁₈alkyl.
 9. A process according to claim 1, wherein in step a3) [ln]represents the polymerization initiator fragment of a polymerizationinitiator of formula (III) capable of initiating polymerization ofmonomers or oligomers which polymerization initiator is selected fromthe group consisting of C₁-C₈-alkyl halides, C₆-C₁₅-aralkylhalides,C₂-C₈-haloalkyl esters, arene sulfonyl chlorides, haloalkanenitriles,α-haloacrylates and halolactones, p and q represent one and the othercomponents are as defined in claim
 1. 10. A process according to claim1, wherein in step a3) the oxidizable transition metal in the transitionmetal complex salt is present as a transition metal complex ion in thelower oxidation state of a redox system.
 11. A process according toclaim 10, wherein the transition metal complex ion is a Cu(I) complexion in the Cu(I)/Cu(II) system.
 12. A process according to claim 1wherein the nitroxyl ether of formula

is used in the polymerization step a1).
 13. A process according to claim1 wherein the optionally used additional ethylenically unsaturatedmonomer is selected from the group consisting of an acrylic acid ester,acrylamide, acryinitrile, methacrylic acid ester, methacrylamide,methacrylnitrile and styrene.
 14. A process according to claim 1 whereinthe polymerization temperature in the steps a1), a2) or a3) is between90° C. and 150° C.
 15. A process according to claim 1 wherein thehydroxy-vinyl aromatic oligomer, cooligomer, polymer or copolymer has aweight molecular weight average from 2000 to 30 000 Daltons.
 16. Aprocess according to claim 1 wherein the iodosilane reagent of step b)is. R₁₃R₁₄R₁₅Sil, wherein R₁₃, R₁₄ and R₁₅ are independently C₁-C₈alkyl,chloromethyl, vinyl or phenyl.
 17. A process according to claim 1wherein the reaction with a halosilane reagent is carried out using achlorosilane reagent from R₁₃R₁₄R₁₅SiCl wherein R₁₃, R₁₄ and R₁₅ areindependently C₁-C₈alkyl, chloromethyl, vinyl or phenyl in the presenceof a halide salt and/or thiol, wherein the halide salt is selected fromthe group consisting of alkaline metal halide, alkaline-earth metalhalide, ammonium halide or phosphonium halide.
 18. A formulatedphotoresist prepared from a polymer obtainable by a process according toclaim 1.